Fastener-driving tool with sound-deadening features

ABSTRACT

A powered fastener-driving tool is provided embodying sounddeadening features which cooperate to materially reduce the level of objectionable noise produced during normal operation of said tool. The noise, in question, is normally produced in tools of this type by repeated contact between hard surfaces of various components thereof. To eliminate, or substantially reduce, these noise sources, sound-deadening material is applied to at least one of the component contacting surfaces in each instance. The material in question is a substantially heat-resistant, rubbery elastomer having a durometer reading within a range of approximately 30 to approximately 70.

1111c ts atent 1 1 Perkins 1 FASTENER-DRIVING TOOL WITH SOUND-DEADENING FEATURES [75] Inventor: Garry R. Perkins, Palatine, 111.

[73] Assignee: Spotnails, Inc., Rolling Meadows,

- Ill.

22 Filed: Mar. 27, 1972 211 App]. No.; 238,057

[52] US. Cl 91/418, 91/461, 92/85, 227/130 [51] Int. Cl. F0lb ll/02, Fl5b 13/042 [58] Field of Search 91/418, 461; 92/85; 227/130; 173/139; 181/36 A [56] References Cited UNITED STATES PATENTS 3,169,452 2/1965 Dugin 227/130 3,181,560 5/1965 Worden et al. 92/223 X 3,231,255 1/1966 Olson 92/85 X 3,320,860 5/1967 Bade 91/461 3,397,828 8/1968 Volkmann 91/461 X 3,512,454 5/1970 Perkins 91/461 3,563,438 2/1971 Doyle et al. 227/130 X FOREIGN PATENTS OR APPLlCATIONS 1,093,638 11/1960 Germany 92/85 Primary Examinerlrwin C. Cohen A powered fastener-driving tool is provided embodying sound-deadening features which cooperate to ma- ,terially reduce the level of objectionable noise pro- 6 Claims, 4 Drawing Figures PATENTEDAPR W 380K281 SHEET 2 [IF 2 FASTENER-DRIVING TOOL WITH SOUND-DEADENING FEATURES BACKGROUND OF THE INVENTION With the increased utilization of powered tools in the general construction industry and the present public consciousness as to noise pollution, it is essential that the objectionable noise produced by such tools when in operation be markedly reduced.

Various attempts to achieve the desired result have heretofore been unsuccessful because of one or more of the following shortcomings: (a) substantial redesigning of the tool or its components was required which materially increased the cost of the tool and sometimes changed the mode of operation of the tool; (b) the operating efficiency of the' tool was materially reduced; (c) maintenance costs were inordinately high; and (d) repeated servicing of the tool was required, causing prolonged periods of down time" for the tool.

SUMMARY OF THE INVENTION Thus, it is an object of this invention to provide a powered fastener-driving tool which produces a very low and unobjectionable level of noise when operating.

It is a further object of this invention to provide a powered fastener-driving tool embodying highly effective sound-deadening features which do not deleteriously affect the operating efficiency of the tool and do not require redesigning of the various components comprising said tool.

It is a further object of this invention wherein sounddeadening features can be readily incorporated in existing tools of this general type.

It is a still further object of this invention to provide sound-deadening features which not only materially reduce the level of objectionable noise produced by the.

operating tool, but in addition, significantly reduce wear between component parts of the operating tool.

Further and additional objects will appear from the description, accompanying drawings, and appended claims.

In accordance with one embodiment of the .invention, a pneumatically powered fastener-driving tool is provided which includes a housing, a cylinder disposed therein, and a driver piston reciprocally mounted within the cylinder for movement between extended and retracted positions. When the piston is in a retracted position, the head thereof is disposed adjacent one end of the cylinder, and when in an extended position, the piston head is disposed adjacent a second, or

opposite, end of the cylinder. Disposed adjacent the cylinder one end is an adjustable valve means which controls the admission of the pneumatic force into the cylinder end behind the driver piston so as to cause the latter to move through its drive stroke. Upon reaching the end of its drive stroke, the piston head engages a bumper piece which absorbs the shock and momentum of the driver piston. When the driver piston reaches the end of the drive stroke, the admission of the pneumatic force is cut-off by the valve means whereby the driver piston automatically returns to its retracted or starting position. Upon reaching its retracted position, one surface of the piston head engages a component of the valve means which is positioned adjacent the cylinder one end. To cushion the engagement of the piston head surface with the surface of the valve means, at least one of the surfaces has applied thereto a heat-resistant, rubbery elastomeric sound-deadening material.

DESCRIPTION For a more complete understanding of the invention reference should be made to the drawings wherein:

FIG. 1 is a fragmentary vertical sectional view of one form of the improved fastener-driving tool taken through the housing and elongated cylinder and showing the driver piston in its retracted position and the valve means in a closed position with respect to the end of the cylinder.

FIG. 2 is similar to FIG. 1, but showing the-piston in its extended position whereby the piston head is in engagement with a bumper piece disposed at the opposite end of the cylinder.

FIG. 3 is an enlarged fragmentary perspective view of the piston head shown in FIGS. 1 and 2.

FIG. 4 is a fragmentary sectional view taken along line 4 4 of FIG. 3.

Referring now to the drawings and more particularly to FIGS. 1 and 2, one form of a pneumatic fastenerdriving tool 10 is shown which is adapted for use in the general construction field to drive nails, brads, pins or the like into a'work piece. If desired, the tool may be of a type used in'driving staples.

In the illustrated tool there is provided a housing 11 in which is fixedly mounted an'elongated cylinder 12. The upper end of the housing is provided with a removable cover 13 and the bottom of the housing is provided with a removable plate 14. Extending laterally from one side of the housing is a hollow handle 15 which not only provides a means for manipulating the tool, but also provides a reservoir in which the high-pressure air accumulates. The outer end of the handle, not shown, is provided with a suitable connector for attachment to an air hose. Depending from the handle 15 is a trigger assembly 16 which is manipulated by the finger of the operator to control firing of the tool. Normally, in a tool of this type, the driver piston 17 will automatically recycle, provided the trigger is continuously depressed, and the discharge end of the tool is properly positioned against a surface of the work piece into which a fastener is to be driven.

The driver piston 17, as seen in FIG. 1, includes an enlarged head 18 and an elongated pusher rod or blade 19 depending therefrom. The lower end portion of the rod 19 extends through an opening 14a formed in the plate 14 which is secured to the bottom side of the housing 11. The rod engages a fastener, not shown, when the latter is disposed within .a firing chamber formed in the nose piece which depends from the underside of the housing. As seen in FIGS. 3 and 4, the piston head 18 is provided with a peripheral groove 20 in which is disposed an O ring 21. The ring is in sliding, sealing engagement with the interior wall of the cylinder. The upper surface of the head 18 may be provided with an annular pocket 22 which is adapted to accommodate a plug 23' of sound-deadening material,

which will be'described more fully hereinafter.

Mounted within. the cylinder and resting upon the plate 14' is a bumper piece 24 which is adapted to abity communicates with an upwardly extending passageway 27 which is vented to the atmosphere through a transversely extending port 28. The valve has an upwardly extending portion 25a which is in sealing, sliding engagement within-the passageway 27. A'bore 30 is formed within the valve 25 and, at predetermined intervals during operation of the tool, provides communication between the portion .of the interior'of the cylinder above the pistonhead and the port 28. so as to exhaust the high-pressure air when the piston head is returning-from its extended position to its'retracted position. A coil spring 31 'is mounted within cavity 26 and' exerts a biasing force on valve 25 causing same to normally assume a closed position with respect to the upper end of the cylinder, see FIG. 1.

When valve 25 is in its fully opened position, as seen in FIG. 2, I the "upwardly protruding portion 25a sealingly engages "aseal piece 32 .which is positioned at the upper end of passageway 27.'When portion 25a engages seal piece 32, communication between the cylinder interior andport 28 is cut off; thus, high-pressure air is introduced into the cylinderinterior above the piston head 18 and around the'valve 2 5. The manner in which the high-pressure air is directedpast valve 25 .is described in Perkins Pat. No. 3,512,454.

Heretofore, in prior tools of this general type, excessive and objectionable noise was produced during operation ofthe tool by reasonof the metal-to-metal 'contac t between various components of the. tool. Certain critical areas in this regard-were (a) between the .coating 34v on the underside of the poppet'valve 25 in addition to that applied on the upper surface of the pismately 70. The composition of the material may be varied and will depend upon the characteristics of the tool in question. For example, when, the tool is a lowpowered type e.g."energy delivered 50-200 foot pounds) the material may be polyurethane per se. Where, however, the tool 'is a heavy-duty or highpowered' type (e.g, energy delivered 200-700 foot pounds) the sound+deadening material'will consist of polyurethane with additives of asbestos and elastomeric fluorine-containing polymers (e.g. up to 60-,percent by weight). I 1 r Plug 23, as seen in FIG. 4, is-provided with a peripheral groove 23a which defines. an annular'lower projection-23b. The projection is adapted to be snug1y"disposed within the pocket 22 and is adhesively secured in place. The portion 230, disposed'abovethe groove 23a, projects upwardly approximately 1/16 of an inch or more, from the surrounding top surface of thehead and is adapted to strike the underside of poppet valve 25 when the head has reached its retracted position, as seen in FIG. 1. Because of the rubbery, elastomeric characteristics of the plug material, the impact'forces created are absorbed within the plug, as well 'as the objectionalsounds associated therewith;

In an alternative construction wherein the upper surface of the piston head'is' not provided with a pocket or recess, the sound-deadening material may be applied over substantially the entire surface in the form of a coating 33, see FIG. 2. s r

A second alternative would be to apply a similar ton head. The combined thicknesses of the coatings 33 and 34 or the thickness of upwardly projectingportion 23c of the plug 23, should be at least approitimately a. 1 /16-of an inc upper surface of the pistonhead and the lower surface ter'at these locations which has been effectively accor n-' plished in the improved 'tool.

In FIGS. 3 and 4, there-is shown the annular plug 23 mounted on the upper surface of the piston head 18. The plug is preferably molded of a relatively heatresistant', rubbery, elastomeric sound-deadening material selected from a group consisting of polyurethane or polyurethane with additives of asbestos and elastomeric fluorine-containing polymers. The hardness characteristics of the material should register a durometer reading .of from approximately 30 to approxi-' 'To minimize or eliminate the objectionable noise which might otherwise result from therepe'ated impacts between the piston head and'the bumper piece, it is desirable to coat the undersurface of the piston head witha layer 35 of sound-deadening material similar to that heretofore described. The thickness of said layer is preferably not less than approximately 1/16 of i r a Th e third causeof objectionable noise production, as

previously described, has been rectified in "the improved tool by the application of a coating 36 applied to the portion 13a of the cover forming the cavity 26 in whichthepoppet valve is movable.

The manner of attaining a quiet operating pneumatically-powered tool by coating various component parts with sound-deadening material, can be readily incorporated in either used or new tools. In either case, no redesigning of the various components or changesin the 7 mode of operating the tool is required.

In lieu of coating the various component parts with,

the sound-deadening material, pieces of said material may be molded to suitable shapesand then be adhesively secured to the surfaces in question.

While the invention in question has heretofore been described in relation to a pneumatically-powered tool, it is not limited thereto, but may be incorporated in various component parts comprising hydraulically or electrically-powered tools as well.

1 Furthermore, the numberv of component .parts to I which the sound-deadening material is applied, and the thickness of the applied material may be varied from that disclosed and will depend upon the type of tool and the amount of power required to operate the tool. Because of the rubbery characteristics of the sounddeadening material, the wear between the heretofore chattering component surfaces has been substantially reduced.

1 claim:

1. A powered fastener-driving tool comprising a housing; an elongated cylinder fixedly disposed within said housing and having an inner end and an outer end; a driver piston mounted within said cylinder for reciprocatory movement between extended and retracted positions, said piston including a head having the periphery thereof in sliding sealing engagement with the cylinder interior wall surface, said head being adjacent said cylinder inner end when said piston is disposed at said retracted position and adjacent said cylinder outer end when said piston is disposed at said extended position; valve means overlying said cylinder inner end and movable relative thereto within a cavity formed in said housing between open and closed positions with respect to said cylinder inner end; and sectional first sound-deadening means of heat-resistant rubbery elastomeric material disposed between said valve means and said piston head, one section of said sounddeadening means being a coating applied to a surface of said valve means adjacent said piston head, and a complemental second section of said sound-deadening means being mounted on a first surface of said piston head adjacent said valve means, said sections having a combined thickness of at least one-sixteenth of an inch and being engageable with one another only upon said piston head being at said retracted position and said valve means being disposed in said closed position relative to the cylinder inner end.

2. The fastener-driving tool of claim 1 wherein said housing cavity is aligned with and adjacent to the inner end of said cylinder and said valve means is mounted therein for reciprocatory movement between said open and closed positions; said valve means, when in said open position, having a second surface thereof of substantial area disposed adjacent a wall of said cavity; and a second sound-deadening means of heat-resistant rubbery elastomeric material positioned between and engaged by said valve means second surface and said cavity wall when said valve means is in said open position.

3. The fastener-driving tool of claim 1 wherein a sec ond surface of said piston head remote from said valve means and opposite the first surface of said piston head has mounted thereon a sound-deadening means of heat-resistant rubbery elastomeric material to engage a bumper piece disposed at the outer end of said cylinder when said driver piston is in said extended position.

4. The fastener-driving tool of claim 1 wherein the material of the sound-deadening means has a durometer reading within a range of from approximately 30 to approximately 70.

5. The fastener-driving tool of claim 1 wherein the sound-deadening means is a material selected from a group consisting of polyurethane or polyurethane with additives of asbestos and elastomeric fluorinecontaining polymers. v

6. The fastener-driving tool of claim 1 wherein the surface of said piston head adjacent said valve means is provided with a pocket, and the second section of the sound-deadening means comprises a substantially flat piece formed of heat-resistant rubbery elastomeric material having a durometer reading within a range of from approximately 30 to approximately said piece having a projection formed on one side thereof which is affixed within said pocket; the opposite side of said piece projecting from the surface of said piston head and engaging the one section of the sound-deadening means mounted on said valve means when said piston is in said retracted position and said valve means is in a closed position. 

1. A powered fastener-driving tool comprising a housing; an elongated cylinder fixedly disposed within said housing and having an inner end and an outer end; a driver piston mounted within said cylinder for reciprocatory movement between extended and retracted positions, said piston including a head having the periphery thereof in sliding sealing engagement with the cylinder interior wall surface, said head being adjacent said cylinder inner end when said piston is disposed at said retracted position and adjacent said cylinder outer end when said piston is disposed at said extended position; valve means overlying said cylinder inner end and movable relative thereto within a cavity formed in said housing between open and closed positions with respect to said cylinder inner end; and sectional first sound-deadening means of heat-resistant rubbery elastomeric material disposed betweEn said valve means and said piston head, one section of said sound-deadening means being a coating applied to a surface of said valve means adjacent said piston head, and a complemental second section of said sound-deadening means being mounted on a first surface of said piston head adjacent said valve means, said sections having a combined thickness of at least one-sixteenth of an inch and being engageable with one another only upon said piston head being at said retracted position and said valve means being disposed in said closed position relative to the cylinder inner end.
 2. The fastener-driving tool of claim 1 wherein said housing cavity is aligned with and adjacent to the inner end of said cylinder and said valve means is mounted therein for reciprocatory movement between said open and closed positions; said valve means, when in said open position, having a second surface thereof of substantial area disposed adjacent a wall of said cavity; and a second sound-deadening means of heat-resistant rubbery elastomeric material positioned between and engaged by said valve means second surface and said cavity wall when said valve means is in said open position.
 3. The fastener-driving tool of claim 1 wherein a second surface of said piston head remote from said valve means and opposite the first surface of said piston head has mounted thereon a sound-deadening means of heat-resistant rubbery elastomeric material to engage a bumper piece disposed at the outer end of said cylinder when said driver piston is in said extended position.
 4. The fastener-driving tool of claim 1 wherein the material of the sound-deadening means has a durometer reading within a range of from approximately 30 to approximately
 70. 5. The fastener-driving tool of claim 1 wherein the sound-deadening means is a material selected from a group consisting of polyurethane or polyurethane with additives of asbestos and elastomeric fluorine-containing polymers.
 6. The fastener-driving tool of claim 1 wherein the surface of said piston head adjacent said valve means is provided with a pocket, and the second section of the sound-deadening means comprises a substantially flat piece formed of heat-resistant rubbery elastomeric material having a durometer reading within a range of from approximately 30 to approximately 70; said piece having a projection formed on one side thereof which is affixed within said pocket; the opposite side of said piece projecting from the surface of said piston head and engaging the one section of the sound-deadening means mounted on said valve means when said piston is in said retracted position and said valve means is in a closed position. 